The choice of MOSFET can be tricky. Seems that irlz44n was discontinued so you may need to find one adapted to the voltage and current you want to handle.
In all the cases you need to get a logic MOSFET too, meaning that they are fully open usually around 1 to 3V.
Also I'm sort of confused as it seems to me that L7812CV is a Voltage regulator, not a MOSFET. So if you are actually using that in the MOSFET spot it will definitively not work.
Especially if you are handling high current or voltage I would recommend using one from a reputable source for your MOSFET, I recently switched from mouser / digikey / aliexpress to mostly use http://www.arrow.com as you get free regular shipping, event if you order a couple of components (no affiliation to them whatsoever).
I didn't think the voltage drop would make enough of a difference to notice, but i guess it does. I might have to research and look for a more efficient Mosfet.
Do you have interest to try OH2 together with MySensors Ethernet Gateway to get working?
I do not have enough force to push developers to make this happen. At the moment there is some problem on this, because full control is not possible. I think that MySensors Serial Gateway is working with OH2, but I don't like to use it. I like to connect my devices into LAN not cabling via old fashioned way using serial wires.
